
ASSEMBLY MANUAL: Glasair SII / III
With the cowl aligned to the spinner backplate, slip some shims (scrap balsa or
cardboard work great) between the cowl and the spinner backplate to hold
everything in position.
Cowl in Position
13. Use a 1.5 mm (
1
/
16
”) bit to drill the 6 cowl mounting blocks for the mounting screws.
Install the screws as you go to help keep things aligned while the next hole is
drilled. Remove the cowl and harden each drilled hole with a drop of thin CA.
Cowl Mounts Drilled & Hardened
14. THIS STEP IS FOR 2-STROKE INSTALLATION
ONLY. Shown below is a 2-stroke installation on a
different aircraft; the Experimental Aircraft Models RV-
7. The size of the model and the engine are
somewhat smaller but the installation requirements
are the same. With a side mounted engine you will
want to use a Pitts style muffler. with the engine and
muffler installed, use the “paper template” method
described in steps 2 & 3 above to locate the exhaust
pipes. Remove the muffler, install the cowl, and mark
the exhaust tube exit positions. This is also a step
where the old adage to “measure twice before cutting
once” will come into play! Use tin snips to cut from
the back of the cowl to the exhaust tube holes - this
gets you close. Reinstall the muffler, slip the cowl into
place and start filing, sanding, or grinding the cowl
opening to fit the muffler. A Dremel grinding tool with
a sanding drum used with care and patience will help
you finish the job quickly. Strive for a minimum 3 mm
(1/8”) clearance between the exhaust tube and the
cowl. In an effort to maintain a cleaner line, note that
the sides of the cut follow the sides of the lower cowl
scoop.
Cowl Fitted Over Muffler
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